Nickel retention by goethite and hematite.
Abstract
The association of nickel with goethite and hematite is of importance for various processes
concerned with nickel extraction. The adsorption of Ni2+(aq) by goethite and hematite in aqueous
solutions were investigated over the pH range of 3 to 9. Similar tendencies were exhibited by both
minerals. Firstly, an increase in nickel adsorption as the pH increased from 3 to 8 was observed.
This can probably be attributed to the fact that the positively charged nickel cations are repulsed
less by the oxide surfaces at higher pH values. Secondly, a sharp decrease in adsorption at pH > 8,
due to a strong increase in nickel precipitation, was observed. Experimentally, it was found that
goethite and hematite samples from different sources differed in terms of their ability to adsorb
nickel over a 24 hour period. Examination of the physical characteristics of the samples used
suggested that the ability to adsorb nickel is determined by their surface areas.
In order to asses the importance of nickel inclusion, relative to nickel adsorption, into the mineral
lattice of the iron oxide minerals under consideration, synthetic goethite and hematite were
synthesised in the presence Ni2+(aq). These experiments were, however, less successful, and further
work needs to be done in this area.
URI
http://hdl.handle.net/10394/14813https://doi.org/10.1016/S0892-6875(00)00140-0
https://www.sciencedirect.com/science/article/pii/S0892687500001400